A backside metal process is one of the key process steps for the fabrication of integrated semiconductor devices. Conventionally, a metal sputtering process or an electron beam deposition (EBD) process may be performed to form a metal film on the backside surface of a wafer in order to improve the heat depression problems of the integrated circuit (IC) formed on the active surface of the wafer opposite to its backside surface. In some cases, the metal film may further provide electrical connection functions to improve the wiring integrity of the IC.
In some typical backside metal process, at least one wafer is disposed on a carrier, and the active surface and backside surface of the wafer are exposed. The carrier is then disposed in a cabinet of a deposition apparatus pervaded by a metal source, whereby a metal film can be formed on the backside surface of the wafer. However, there are still some drawbacks, for example, since the backside metal process is carried out without shielding the active surface of the wafer, thus some metal ions may be deposited thereon, and these metal ions may be further oxidized to contaminate the active surface, such that wafer may be smudged and active surface discoloration may occur. These problems may get worse, especially in the course of some thermal reactions or at the time of vacuum release.
Therefore, there is a need of providing an advanced substrate carrier, an apparatus for performing a deposition process and a method applying thereof in order to prevent wafer discolored or smudged and improve the production yield of the integrated semiconductor devices formed on the active surface of the wafer.